NullController - remove a bunch of methods that were originally part of IController but no longer are, and clean up the code a bit

BizHawk.Emulation.Common/Base Implementations/NullController.cs

@@ -7,16 +7,26 @@
 	/// <seealso cref="IController" />
 	public class NullController : IController
 	{
-		public ControllerDefinition Definition { get { return null; } }
-		public bool this[string button] { get { return false; } }
-		public bool IsPressed(string button) { return false; }
-		public float GetFloat(string name) { return 0f; }
-		public void UnpressButton(string button) { }
-		public void ForceButton(string button) { }
+		public ControllerDefinition Definition
+		{
+			get { return null; }
+		}
 
-		public void SetSticky(string button, bool sticky) { }
-		public bool IsSticky(string button) { return false; }
-		private static readonly NullController nullController = new NullController();
-		public static NullController GetNullController() { return nullController; }
+		public bool this[string button]
+		{
+			get { return false; }
+		}
+
+		public bool IsPressed(string button)
+		{
+			return false;
+		}
+
+		public float GetFloat(string name)
+		{
+			return 0f;
+		}
+
+		public static NullController Instance = new NullController();
 	}
 }

BizHawk.Emulation.Cores/Consoles/PC Engine/PCEngine.cs

@@ -141,7 +141,7 @@ namespace BizHawk.Emulation.Cores.PCEngine
 
 		private void Init(GameInfo game, byte[] rom)
 		{
-			Controller = NullController.GetNullController();
+			Controller = NullController.Instance;
 			Cpu = new HuC6280(MemoryCallbacks);
 			VCE = new VCE();
 			VDC1 = new VDC(this, Cpu, VCE);

BizHawk.Emulation.Cores/Consoles/Sega/SMS/SMS.cs

@@ -102,7 +102,9 @@ namespace BizHawk.Emulation.Cores.Sega.MasterSystem
 				HasYM2413 = true;
 
 			if (Controller == null)
-				Controller = NullController.GetNullController();
+			{
+				Controller = NullController.Instance;
+			}
 
 			Cpu = new Z80A();
 			Cpu.RegisterSP = 0xDFF0;